Bidding rounds for the country's biggest-ever spectrum auction will begin from 29th of next month in which mobile airwaves worth Rs 5.63 lakh crore at the base price value will be put up for sale. The total quantum of spectrum being put for auction includes about 197 Mhz of frequencies in 1800 Mhz band and 37.5 Mhz in 800 Mhz band. Addressing a press conference in New Delhi, Telecom Secretary J S Deepak said, the government expects to raise at least Rs 64,000 crore from the auction of about 2,354.55 Mhz of spectrum and Rs 98,995 crore from various levies and services in the telecom sector in this financial year.Mr Deepak said, the spectrum will be assigned to the successful bidder within 30 days from the date of receipt of due payment. He said, the government has also reduced interest on installments to 9.3 per cent from about 10 per cent earlier. He said, the government believes that the auction will provide a great opportunity to the existing service providers as well as new entrants.